Classic garden bench
This garden bench is truly a North American classic.
Often, one of the most desired pieces of outdoor furniture is a garden bench. Many of us have just the ideal spot for this project, be it on the front porch so we can watch the world rush by, on the back yard deck, or even tucked away in a secluded spot as part of the garden setting.
During my research for the ideal bench, I looked at some of the commercial offerings at my local furniture store. Many were light duty models made out of pine or cedar. Others were high-end commercial models, made from teak and mahogany and would certainly put my budget in a tailspin.
How do we get the quality of those high-end commercial models without considering a second mortgage on our homes? Well, as a woodworker we have the option to build the project ourselves with substantial savings and, most likely, at a higher quality. First, decide on the basic design and then choose the construction material.
After looking at many styles I decided to design and build a garden bench that is considered more North American in design. The English style seemed to have thin legs, curved arms, and delicate lines. The American style tended to be heavier in appearance with thick legs and flat wide arms. It makes a very strong visual statement.
The bench has heavy 3” square legs and thick, 1 1/2” arms. Stringers and seat slats also continue the theme as they are constructed out of 1 1/2” thick material.
There are many woods to choose from and, because I wanted a bench that would last for years, I decided to use a hardwood. Ash is a hardwood used in the cabinet making industry because it resembles oak but has a tighter grain structure. It’s a heavy, durable wood that, when properly protected, will stand up to a lot of abuse and provide many years of useful service.
Glue up 1 1/2” thick boards to form the front and rear legs. Four pieces are needed for the two front legs. Each leg requires two boards at 1 1/2” x 3” x 24”. Each of the two rear leg blanks are formed by gluing two 1 1/2” x 5 1/4” x 34” boards as shown. Use moisture cured polyurethane glue for each of the blanks.
TIP: If the wood is cracked from poor air-drying, as was the case with the ash that I was using, then fill the voids with polyurethane glue and a little sawdust. You’ll be able to sand the area when the glue sets and eliminate a place where water can penetrate. Mortise and tenon joinery is used throughout this project as it’s an ideal joint to connect many of the right angle intersections. Waterproof polyurethane glue proved to be an excellent choice for all these joints. I opted to create thick material for the legs by gluing 1 1/2” boards together. This method is ideal, as I needed 5 1/2” wide by 3” thick wood blanks for the curved rear legs. All the other pieces for this bench are no more than 1 1/2” thick.
Dress the front legs to a finished size of 3” x 3” x 23 1/4”.
Form a tenon on one end of each front leg assembly that’s 3/4” high and 1 1/2” square on the centre of the leg.
Next, mark and cut the mortises on the front legs as shown.
Sand the front legs and soften the edges with a 1/4” round over bit in a router.
Layout the curved back leg assemblies on the 3” x 5 1/4” x 34” wood blanks as shown in the illustration.
Using a bandsaw is the easiest way to cut the back legs. However, it’s possible to use a jigsaw that has a fairly long travel distance if you haven’t got access to a bandsaw. After cutting, clamp the legs together and sand so they will be the same size.
Form the mortises in the rear legs. Prior to cutting them, verify that their position is the same on both back and front legs for the seat supports and leg rails.
The back assembly must be inserted into the rear legs prior to attaching the front and rear sections of the bench. First, we need an upper back rail that has overall dimensions of 1 1/2” x 5 1/2” x 68”, cut as shown. I created a curved template by marking lines parallel to each other, spaced one inch apart, over an 8” run. Beginning at 3” from the bottom, I marked a point on each line 3/8” higher than the last. This slight upward curved template allowed me to mark the rail slope, starting at 10” from each rail end.
Cut the curve using a jigsaw and sand.
Next, cut a lower back rail measuring 1 1/2” x 3” x 68”.
Using a router with a 1/2” straight cutting bit or a table saw equipped with a dado blade, plow a 3/4” wide by 1/2” deep dado in the center of the upper back rail lower side and top side of the bottom back rail. These dadoes will accept the 3/4” thick.
TIP: Mortises can be cut in many ways. If you have a dedicated square chisel mortiser, it’s an easy process. If you haven’t got access to one of the machines, a drill press will allow you to make excellent round corner mortises. The tenon corners can be rounded over with a wood file for a tighter fit.
Form the two 1/2” thick by 1 1/2” wide by 2” long tenons on each end of the upper and lower back rails.
Prepare 14 back slats at 3/4” thick by 2 1/4” wide by 14” long. You will also need to cut 26 slat spacers at 1/2” x 3/4” x 2 1/4” long. As well, four spacers at 1/2” x 3/4” x 2 1/8” long are needed. These shorter pieces are the first and last spacers on the upper and lower rails.
Insert the spacers and slats into the upper and lower back rails. Beginning at one end, insert a 2 1/8” spacer with glue and a small brad nail from behind to hold the spacer until the glue sets. Remember to use galvanized brads. Next, install a slat, then a 2 1/4” spacer and so on. Work on the upper and lower rail, securing each spacer and slat as they are installed until all the parts are attached. The last piece on each rail is the 2 1/8” spacer. Assemble the back to the rear legs.
A front seat rail to join the two front legs is required. This rail measures 1 1/2” x 3” x 68” and has a tenon on each end as illustrated. Round over the bottom edge.
Attach the two front legs to the front seat rail. If available, use an 8’ pipe clamp to secure the assembly until the glue dries.
Cut two lower leg rails at 1 1/2” x 3” x 18”. Each end of these rails has a tenon at 1/2” thick by 1 1/2” deep and 2” long. After cutting the tenons, round over all edges with a 1/4” round over bit in a router. Test fit the joints and reference each with a witness mark for later assembly.
We now need two seat supports, which are exact copies of the lower rails. However, we will scribe and cut a curve for the seat slats in the next step. These supports are initially cut at 1 1/2” x 3” x 18” with two tenons at 1/2” thick by 1 1/2” deep by 2” long. After forming the tenons, reduce the depth of each by 1/4” to clear the intersecting joint of the front seat rail and lower back support rail.
Mark a point at the center of the seat support, 2 1/4” up from the bottom. Using a stick compass with a 36” radius, draw a curve. Cut both supports using a bandsaw or jigsaw. Clamp the two pieces together and sand smooth.
Round over the bottom edges of the seat supports.
Attach the front and rear assemblies with the lower leg rails and the seat supports. Glue and clamp in position.
Because the seat boards span almost six feet, a center support rail will be installed. This rail is first cut at 1 1/2” x 2 1/4” x 16 1/4” long. We want to duplicate the seat support curve so we’ll begin the radius line 3/4” in from the front to a point that is 1/2” short of the back edge. The back is also angled to meet the lower back rail. Lay a straight edge from seat support to seat support to determine the correct position of the center support board. Attach the center support with glue and screws. Counterbore the screw holes and insert wood plugs.
Cut six seat boards. Five are 1 1/2” thick by 2 3/4” wide by 71” long and the sixth, which is the front board, is trimmed to 65” long to fit between the front legs. Sand and round over the top edges.
TIP: Cut the mortise first. Then, using a file, form the slightly oversized tenons until they fit snugly into their respective mortises. This procedure insures strong joints.
Space the seat boards at 1/4” starting from the rear. This spacing will force the front seat board to overhang the front seat rail. Attach the seat boards using one 2” screw per seat support rail, for a total of three screws per board. The front board has five 2” screws with the two extra being between the center and outside seat supports. Fill the counterbored holes with a wood plug and sand flush.
The armrest is formed from a board 1 1/2” thick by 5 1/2” wide and 21” long. Layout the pattern on the board as shown and cut the arm.
The armrest is slightly angled where it meets the back leg. I found our angle to be eight degrees, however I suggest that you determine the best angle for your bench. Lay a level board across the front leg on the shoulder beside the tenon. Mark a line on the board where the back leg intersects. Measure the angle and cut each armrest. Make sure you place the arm correctly when cutting the angle as you are creating a right and left side.
Next, place each arm in its final position on top of the leg tenon and mark the mortise outline. There will be a slight error in the mortise position because the arm is not in its final position (it’s higher by the height of the tenon). Take this error into account when cutting the mortise. The arm will move slightly forward in the final home position after the mortise is completed.
After completing the mortise and verifying the fit is correct, sand and round over the upper and lower surfaces of both arms. Round over the front curve but do not round over the angled end.
Drill two countersunk pocket holes on the underside of each arm in the end where the arm meets the rear leg. Pilot drill these holes so they exit in the middle of the arm’s back end. Apply glue to the mortise as well as the back surface of the arm and attach with two 2 1/2” screws through the pocket holes. Clamp the front joint.
TIP: Use a stop block. Clamp a board on the line where the top surface of the arm meets the back leg. This will prevent the arm from creeping upward as you tighten the pocket screws.
Your classic garden bench is now ready for final sanding and finishing.
I tested various methods of attaching the arm to the rear legs. Using a mortise and tenon would be fine but the rear leg angle could cause fitting problems. Dowels are a good alternative, but I found the pocket screw method to be the easiest and most accurate.
There are areas where two mortise and tenon joints intersect. It depends where you place the back assembly mortises. You can move the joints slightly towards the rear of the leg to avoid this situation, however, I prefer to trim one of the tenons during dry fitting.
Ash is a nice hardwood to work with for a project of this type. The boards for this chair had been air dried for a couple of years and did have some checks and cracks. However, because I was gluing stock for the legs, I could choose the best outside surfaces.
Use exterior rated fasteners and glues. I found the polyurethane glue to be an excellent choice for this project. It set up in a reasonably short time and the joints were solid.